I've got an '09 model with 29hp kawi just like your's and it got better on fuel after 75 hours or so. Another thing to remember is that it uses alot of gas just running whether your putting around on a 10K lawn or a 5 acre estate its gonna use about 1.75 gallons per hour. BTW you wasted money on a stripe kit, it will do that without it. I have found that the best blades for me are the Exmark highlift mulching blades with side discharge in the fall and regular Exmark or Oregon highlift for spring and summer. I also mow Tall Fescue at 4" and mixed grasses at 3.25". Hope this helps, enjoy the new mower.
Knowledge is knowing a tomato is a fruit, wisdom is not using it in a fruit salad.